1. Field of the Invention
This invention relates to a process for producing a photoconductive member effective for formation of a photoconductive layer on a given substrate by utilization of discharging such as glow discharging or arc discharging.
2. Description of the Prior Art
When it is desired to form a photoconductive layer having desirable characteristics on a given substrate by utilization of a plasma excited by glow discharging of a gaseous starting substance for formation of a photoconductive layer constituted of, for example, an amorphous material having a matrix of silicon atoms in a deposition chamber which can be reduced in pressure, particularly in the case of a layer with a large area, it is very difficult to increase the layer formation rate, as compared with visual vacuum deposition methods, while controlling the layer thickness uniformly over the whole area and also uniformly the physical characteristics such as electrical, optical and electro-optic characteristics as well as the quality of the product.
For example, when an amorphous silicon layer containing at least one of hydrogen atoms or halogen atoms (X) [hereinafter abridged as "a-Si(H, X)"] is intended to be formed on a substrate by decomposition of a gas such as SiH.sub.4, Si.sub.2 H.sub.6 or SiF.sub.4 or a mixture of SiH.sub.4 and SiF.sub.4 using a discharging energy for utilization of electrical properties of the resulting layer, the electrical characteristics of the layer are greatly dependent on the layer deposition rate and the substrate temperature upon forming the layer. Therefore, for the purpose of obtaining uniform electrical characteristics and improved layer quality over the entire region of the layer, it is necessary to lower the layer deposition rate and elevate the substrate temperature.
On the other hand, for improvement of productivity and mass production capability, it may be considered to increase the discharging power and gas flow amount for increase of the layer deposition rate. But, when discharging power and/or the gas flow amount is increased for increase of the layer deposition rate, the layer formed will markedly tend to be lowered in electrical, optical and photoconductive characteristics and increased in dependency of such characteristics on work environments, whereby it is very difficult under the present situation to form a layer of good quality. Thus, for the purpose of commercial production of a photoconductive member having a photoconductive layer constituted of an amorphous material containing a matrix of silicon atoms, it is necessary to improve the productivity and mass production capability, including reproducibility, while also keeping good and uniform layer quality closely correlated with photosensitivity, characteristics during repeated usage and the characteristics dependency on the environmental conditions employed.